1. Field of the Invention
The present invention is related in general to a hopper car for carrying bulk materials and more particularly to a hopper car gate with opposed double doors.
2. Description of Related Art
Hopper cars are commonly used to transport and sometimes store bulk materials. Hopper cars include one or more hoppers which hold bulk materials or other cargo for shipment. Each hopper has a discharge opening at its bottom in order to discharge the cargo upon arrival at its intended destination. A gate is joined to each opening to control the discharge of cargo from the hopper. Typically, the gate will have a frame defining an opening and a door moveable between a closed position which blocks the opening and an open position which allows cargo to exit through the opening. An opening mechanism allows a user to move the door between its closed and open positions.
Some commonly transported bulk materials have difficulty exiting through standard hopper gates. In particular, dried distillers' grains, which are a byproduct of ethanol production from corn, are sticky and may form clumps blocking the opening of a standard hopper gate. A bigger discharge opening is needed to effectively discharge sticky cargo such as dried distillers' grains. Increasing the discharge opening on a standard hopper gate presents a problem because of the increased cargo load supported by the door. This increase in cargo load translates into an increase in operating torque necessary to open the door. The operating torque cannot be increased beyond levels making it impractical to operate the door. Additionally, the Association of American Railroads (AAR) sets industry standards regulating the maximum amount of breakaway torque required to open a hopper door. Therefore, there is a need for a hopper car gate which can effectively discharge sticky bulk materials while having a practical operating torque.